JPH0743924B2 - Information storage method and information storage element - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of storing information at high density and a device using the same. More specifically, the present invention relates to a memory element that densifies by writing information in the domain wall of a magnetic bubble.

(Prior Art) In a magnetic bubble memory device that uses a magnetic bubble as an information carrier, it is generally performed to associate the presence or absence of a magnetic bubble with (1,0) of binary data information. The information storage density of this magnetic bubble memory element is defined by
The magnetic bubble transfer pattern cycle itself. Therefore, in order to achieve high density storage, it is necessary to shorten the transfer pattern cycle. The determination of the transfer pattern cycle depends on the exposure / etching technology level at that time. This state of the art is such that a pattern of at most about 0.8 μm can be processed by using a usual optical exposure method.

Even with the ion implantation device that has the highest memory information density by using this exposure etching technology, the storage density is at most 10 Mb / cm ²
It is a degree. In recent years, as the storage capacity of semiconductor IC memory devices has increased, magnetic storage devices that are required to have backup functionality have also been required to have higher storage density. Therefore, the conventional magnetic bubble memory device that transfers magnetic bubbles has become insufficient in terms of storage density.

On the other hand, in terms of storage density, a Bloch line memory device capable of dramatically increasing the storage density in comparison with the conventional magnetic bubble memory was proposed in Japanese Patent Application No. 57-211747. This memory element is characterized in that information is stored depending on the presence or absence of a pair of vertical Bloch lines, which is a form of a magnetization state of a domain wall portion which is a boundary between striped magnetic domains existing in a magnetic material thin film capable of holding magnetic bubbles. . A unit of information is not defined by the presence or absence of magnetic domains as in the magnetic bubble memory device described above, but by the existence of vertical Bloch line (VBL) pairs, which are finely magnetized structures in the domain walls of the magnetic domains. Therefore, the memory density is extremely high. It is stated therein that the storage density is about 100 times higher than that of a magnetic bubble memory device having the same stripe domain width.

However, in order to operate the Bloch line memory stably, it is necessary to provide a bit position forming pattern for VBL pair stabilization on the domain wall of the striped magnetic domain. It is described on page 83 of the Annual Meeting of the Applied Magnetics Society of Japan. Providing the bit position forming pattern means that the pattern accuracy is limited by the same exposure etching technique as the conventional magnetic bubble memory device. Therefore, in the Bloch line memory element that performs such bit position formation, the storage density is almost the same as that of the conventional magnetic bubble memory element, and the advantage of using a minute VBL pair as a storage unit is lost.

Further, in the Bloch line memory device, information is read out depending on whether or not the VBL pairs can be converted into magnetic bubbles at the tips of the striped magnetic domains which are also the transfer of VBL pairs arranged periodically. The period of the striped magnetic domains becomes shorter as the density of stored information becomes higher. VB is added to the tip of each striped domain with such a short period.
Providing a VBL pair that converts an L pair into a magnetic bubble is extremely difficult from the above-mentioned exposure etching technique.

(Problems to be Solved by the Invention) It is difficult to increase the density of a conventional magnetic bubble memory device, and the complexity of a conversion unit from a VBL pair to a magnetic bubble of a Bloch line memory device is solved by the present invention. Is the main problem. A further object of the present invention is to provide a memory element with a higher density by using the same exposure etching technique as that used in forming a conventional magnetic bubble memory element.

(Means for Solving the Problems) In the information storage method of the present invention, a thin piece of magnetic material capable of holding and transferring a magnetic bubble, a plurality of loop-shaped magnetic bubble transfer paths provided on the thin piece, and the loop. Information input magnetic bubble transfer path and information output bubble transfer path, which are close to the linear transfer path,
A magnetic bubble transfer gate for connecting the above two types of transfer paths, a mutual conversion means for magnetic bubbles and stripe magnetic domains provided in the information input magnetic bubble transfer path and the information output bubble transfer path, and the stripe magnetic domains. (L ₁ , l ₂ , ..., l _n ) (l ₁ , l ₂ , ..., l _n ) (in the magnetic memory element having means for writing a pair of vertical Bloch lines on the domain wall of Where l _I =
For binary data information represented by 1 or 0), By injecting a pair of vertical Bloch lines of the above into the boundary domain wall of the magnetic bubble, n-fold information can be stored for each one magnetic bubble.

Further, the information storage element of the present invention includes a thin piece of magnetic material capable of holding and transferring magnetic bubbles, a plurality of loop-shaped magnetic bubble transfer paths provided on the thin pieces, and information input in the vicinity of the loop-shaped transfer path. Bubble transfer path and information output bubble transfer path,
A magnetic bubble transfer gate for connecting the above two types of transfer paths, a mutual conversion means for magnetic bubbles and stripe magnetic domains provided in the information input magnetic bubble transfer path and the information output bubble transfer path, and the stripe magnetic domains. Means for writing a pair of vertical Bloch lines on the domain wall and a means for detecting the number of vertical Bloch line pairs in the striped magnetic domain, and the Bloch line logarithmic detection means is a Bloch line stable with a maximum Bloch line number -1. Bloch line-to-magnetic bubble conversion part composed of a comb-shaped conductor pattern forming a position, a local bias magnetic field modulation conductor pattern, a stripe magnetic domain tip extended conductor pattern, and a stripe magnetic domain chopping conductor pattern, and different magnetic domain walls generated thereby. By moving a magnetic bubble with a state in a gradient bias magnetic field Discriminating the magnetic bubble domain wall state of respectively, it is characterized by counting the magnetic bubble number of a particular domain wall state.

(Example) The principle and operation example of the present invention will be described with reference to the drawings. An information storage method according to the principle of the present invention will be described with reference to FIGS. 1 (a) and 1 (b). FIG. 1 (a) schematically shows a plan view of the magnetic bubble. Since the magnetization directions indicated by 4 are different inside and outside the magnetic bubble 1, a domain wall 2 is formed at the boundary portion. The magnetization direction at the center of the domain wall lies in the plane. The magnetization direction in this domain wall has a finer structure, and there may be a vertical Bloch line (VBL) having a portion in which the magnetization is perpendicular to the domain wall. In one VBL section,
The magnetization is twisted 180 ° in the plane. VB twisted 180 °
If you make a pair with L and make it VBL pair 3, this pair becomes stable in the domain wall.

The principle of the present invention is to write data information in the domain wall of the magnetic bubble in correspondence with the number of VBL pairs. For example, as shown in FIG. 1 (b), it is possible to uniquely assign the number N _B corresponding to a binary data information sequence. In this example, N _B = 1 + l ₁ + l ₂ × 2 + l ₃ × 2 ² + l ₄ × 2 corresponding to binary data (l ₁ , l ₂ , l ₃ , l ₄ ) (where l _i = 1 or 0) It is uniquely determined by the relationship of ³ . This relationship holds in reverse, and if N _B is determined, the binary data (l ₁ , l
₂ , l ₃ , l ₄ ) is also uniquely determined. That is, when N _B VBL pairs exist in the domain wall of the magnetic bubble, the magnetic bubble represents the data of (l ₁ , l ₂ , l ₃ , l ₄ ). Generalizing this, In one magnetic bubble that has a domain wall with VBL pairs of
This means that n binary information of (l ₁ , l ₂ , ..., L _n ) can be stored.

In this way, by storing one magnetic bubble having n pieces of information in the loop-shaped magnetic bubble transfer path, as in the conventional magnetic bubble memory device, the storage density can be increased n times at a stroke. I understand. At this time, it goes without saying that the pattern accuracy of the magnetic bubble transfer path itself is no different from the conventional one.

Next, the element structure of the present invention and its operation will be described with reference to FIG. In the magnetic bubble holding material thin film 10, a bubble generator 20, a VBL pair writing section 22 having a means for mutual conversion of magnetic bubbles into stripe magnetic domains, a major line transfer path 23,
Magnetic bubble transfer path 21, magnetic write transfer gate 24, magnetic bubble transfer minor loop 5, lead-out transfer gate 3 leading to the generated magnetic bubble VBL pair write unit
4, VBL pair number counting unit 32 with mutual change means for stripe domain of magnetic bubble, take-out major line transfer path 3
3. A magnetic bubble transfer path 31 that guides the magnetic bubbles generated in the counting section to the magnetic bubble detector 30 is formed by using a process such as a membrane, exposure, and etching, and all of them are used as the memory chip 11.

This basic operation is as follows. First, a magnetic bubble is generated by the generator 20. The generated magnetic bubbles are transferred on the transfer path 21 and guided to the VBL pair write unit 22. In the VBL pair write unit 22, the bias magnetic field is locally lowered, and the magnetic field bubble is expanded in the stripe domain shape. This function constitutes the mutual conversion means of the magnetic bubble and the striped magnetic domain. A predetermined number N of VBL pairs are set in this striped magnetic domain by the method shown on page 224, Proceedings of the 1st Annual Meeting of the IEICE General National Conference, published in March 1986.
Write only _B. Next, this is again compressed into a magnetic bubble and transferred on the major transfer path 23. This process is repeated one after another, and when the magnetic bubbles are aligned at the positions corresponding to the minor loops on the major transfer path, the write transfer gate 24 is opened and the magnetic bubbles are transferred to the minor loop transfer path 5. Furthermore, this process is repeated for the number of magnetic bubbles that can be stored in the minor loop,
Fill with magnetic bubbles with VBL pairs. It is well known that the transfer of magnetic bubbles is extremely stable in a minor loop filled with magnetic bubbles.

To read the information, proceed as follows. The magnetic bubble with the VBL pair in the minor loop 5 is taken out, the transfer gate 34 is opened, and the major line 33 is taken out.
Move to. Transfer major line 33 to VB magnetic bubble
It is led to the L pair number counting unit 32. In the number counting unit 32, the bias magnetic field is locally reduced to expand the magnetic bubble into stripe magnetic domains. Next, the maximum number of VBL pairs written in this stripe magnetic domain is set to M by using a method described in detail later.
When Cut out individual magnetic bubbles. At this time, the domain wall states (S = −1) of the N _B −1 magnetic bubbles and the remaining M− (N _B −
1) The domain wall state (S = 0) of each magnetic bubble is different,
The information contained in the first magnetic bubble is determined by discriminating the magnetic bubbles having different domain wall states.

A method of driving the memory element of the present invention will be briefly described with reference to FIG. The counter 62 and the modulator 61 are connected to the VBL pair write unit of the memory chip 11 described above. This is connected to the input section 60. Modulator 61, depending on the binary input data stream
Then, divide the data into n pieces. Then, n pieces of data are input to the counter 62, a number N _B corresponding to the data is generated, and N _B times VBL pair write section excitation pulses are generated.

The reverse process is performed when reading data. The counter 72 is connected to the bubble detector section of the memory chip 11. The counter 72 is coupled to the demodulator 71, from which the output 70 is obtained. First, from the detector unit, N _B -1 specific domain wall states (S
= -1) corresponding to the magnetic bubbles, N _B -1 outputs are obtained. This is counted by the counter 72 and input to the demodulator 71. The demodulator 71 generates n pieces of data corresponding to N _B -1. This is the data output 70. This data reading is not non-destructive as described later. Therefore, in order to ensure the preservation of the data, the output data obtained from 70 is also led to the input 60 to rewrite the data.

Next, the counting of the VBL pairs of the N _B pairs and the VBL pairs of the magnetic bubbles in the domain wall will be described in detail. First, a VBL-magnetic bubble converter for converting the number of VBL pairs into the number of magnetic bubbles in a specific domain wall state will be described with reference to FIGS.
As shown in Fig. 4, a magnetic bubble 1 with N _B VBL pairs
Is transferred on the major transfer path 33 and comes to this converter. This converter section is composed of a VBL pair fixing conductor pattern 35 in a blind shape, a reciprocating conductor pattern 36, 36 'for local bias magnetic field modulation, a stripe magnetic domain tip extension pattern 37, and a stripe magnetic domain chop conductor pattern 38, 38'. , Each conductor pattern is electrically insulated.

Next, as shown in FIG. 5, while applying an in-plane magnetic field Hin40, a current is applied to the reciprocating conductors 36, 36 'to lower the bias magnetic field at the central portion and the magnetic field bubble 1 is expanded to the striped magnetic domain 15.
The VBL pair 3 existing on the magnetic domain wall of the magnetic bubble is also dispersed on the magnetic domain wall of the stripe magnetic domain 15 as the magnetic domain extends. However, its stable position is not fixed. Due to the presence of Hin, one VBL pair is separated at both ends of the stripe magnetic domain, and each VBL faces the direction of Hin and is always stable.

Next, as shown in FIG. 6, a current is applied to the blind conductor pattern 35. Since the local in-plane magnetic field 42 generated in each cross of the blind-shaped conductor pattern 35 and the magnetization direction of the domain wall between the VBL pairs match each other, the VBL pairs are stabilized across each cross. Twice the number of bars is VBL
Equal to the number of stable positions in the pair. The total number of VBL pairs is twice the number of crosspieces +1 when the two VBLs at both ends of the stripe magnetic domain are counted as a pair. At this time, the number of bars is And the number of fixed positions of the VBL pair is Therefore, the maximum number of write VBL pairs is -1.

At this time, a bias pulse magnetic field is applied as shown at 41 in FIG. This bias pulse magnetic field can be easily invented by, for example, reducing the current value applied to the local magnetic field generating reciprocating conductor pattern 36 in a pulse shape. By applying the bias pulse magnetic field, the domain wall 2 of the stripe-shaped magnetic domain 15 moves, and this movement causes a gyroscopic force on the VBL, resulting in a VBL.
The pair moves. That is, the VBL pair of 3a in FIG.
Move to position. Point 3b where VBL pair does not exist in Fig. 6
Moves to position 3b in FIG. At this time, a current is applied to the conductor 38 'to generate the VBL local fixed magnetic field so that the VBL3c at the tip of the stripe magnetic domain does not move. As a result, there is a pair of VBL and one VBL at the tip of the stripe magnetic domain. VBL pairs at other positions move one stable position each.

Further, as shown in FIG. 8, a current pulse is applied to the magnetic domain tip stretching pattern 37 to stretch the magnetic domain tip beyond the magnetic domain chop conductor patterns 38, 38 '. Then, as shown in FIG. 9, current pulses are applied to the magnetic domain chop conductor patterns 38, 38 'to divide only the tips of the stripe magnetic domains.
A magnetic bubble in a domain wall state (S = -1) containing two pairs of VBLs having a negative sign is generated at the tip portion generated by the cutting. Repeating the above sequence of FIG. 6 to FIG. 9 again, this time, the VBL shown in 3b of FIG.
Since there is no pair, a pair of VBL exists in the domain wall of the magnetic bubble generated by the disconnection. This corresponds to S = 0 in the domain wall state.

The above operation When it is repeated, M magnetic bubbles are generated by being divided. The generated M magnetic bubbles are divided into N _B -1 S = -1 state magnetic bubbles and M- (N _B -1) S = 0 state magnetic bubbles. The magnetic bubble in the domain wall state with S = 0 has a pair of negative sign VBL as shown in FIG. S =-
The magnetic bubble in the domain wall state of 1 has two pairs of negative sign VBL. It is well known that these magnetic bubbles in the domain wall state of S = 0 are so-called soft bubbles, and the magnetic bubbles in the domain wall state of S = −1 are well known as hard bubbles.

As shown in Fig. 11, the magnetic bubble is biased with a bias magnetic field gradient ▽ Hb.
When placed inside, the magnetic bubble in the S = 0 state moves in the direction of the magnetic field gradient, and the magnetic bubble in the S = −1 state moves in the direction deviated from the magnetic field gradient direction by a constant angle ρ. Generally known as the skew effect of hard bubbles.

Also, as shown in FIG. 12, due to the magnetic wall state of the magnetic bubble,
It is known that the magnetic bubble extinction magnetic field H ₀ and the extinction critical diameter d ₀ are different. That is, as compared with the magnetic bubble of S = 0, the magnetic bubble in the S = −1 state has an extinction magnetic field ▲ H ^′ ₀ ▼.
Is high and the extinction critical diameter ▲ d ^′ ₀ ▼ is small.

The method of discriminating the domain wall state using the above properties will be specifically described below. FIGS. 13 and 14 (a) and (b) show a method for discriminating the first domain wall state using the skew effect of hard bubbles. First, in FIG. 13, the VBL pair counter 32 is provided with a magnetic bubble transfer path 31 formed of two layers of zigzag conductor patterns 81 and 82. When alternating currents 90 ° out of phase with each other are applied to the conductor patterns 81 and 82, the magnetic bubbles are transferred along this transfer path. At this time, the transfer direction can be two different directions due to the skew effect of the magnetic bubbles. Therefore, if the magnetic bubble detectors 30 and 30 'made of a permalloy thin film or the like are arranged ahead of this transfer path (total length L), the signal from the detector 30 at the position L · tan ρ with respect to the skew angle ρ If the domain wall state of the obtained magnetic bubble is S = -1, and a signal is obtained from the detector 30 'located in the straight forward direction, it is proved that the magnetic bubble has S = 0.

14 (a) and 14 (b) show another example of the domain wall discriminating means using the skew effect of hard bubbles. A magnetic bubble transfer path 31 formed by a stripe-shaped conductor pattern 84 in contact with the VBL pair counting section 32, an ion implantation connecting circular pattern 83 in contact with the stripe-shaped conductor pattern 84, and a magnetic bubble detector attached to the transfer path 31.
This discrimination means is composed of 30. When the magnetic bubble 1 is generated in the VBL pair counter, the current pulse I is applied to the conductor pattern 84. The magnetic field of the bias component generated from the conductor pattern has a gradient ▽ Hb in the width direction of the conductor pattern 84. Therefore, the magnetic bubble of S = 0 moves to the cusp portion 83a which is the magnetic bubble stable position of the concatenated circular pattern. On the other hand, S =-
The magnetic bubble of 1 moves to the cusp portion 83b one bit ahead due to the skew effect. After the movement of the magnetic bubbles is completed, the application of current to the conductor pattern 84 is stopped. After that, after rotating the in-plane magnetic field for two cycles, the next magnetic bubble is generated by the VBL pair counter 32, and the same sequence is performed. Repeat. The magnetic bubble detector 30 attached to the magnetic bubble transfer path 31 detects the magnetic bubble output V _s at the earlier clock timing of the two clocks of the rotating magnetic field H _r , as shown in FIG. 14 (b). If it is, it is determined that the magnetic bubble is in the domain wall state of S = −1. When V _s is detected at the later clock timing, it is determined that this is a magnetic bubble in the domain wall state with S = 0.

Next, FIG. 15 (a) shows a second discriminating means of magnetic bubbles having different domain wall states using the magnetic bubble extinction magnetic field difference.
This will be described with reference to (b) and FIG. This is a means of using the difference in the annihilation magnetic fields of magnetic bubbles having different domain wall states. As shown in FIG. 15A, the magnetic bubble transfer path 31 is arranged near the VBL pair counting section 32. In this example, this transfer path is formed by an ion implantation connecting circular pattern.
In the middle of this transfer path, a magnetic bubble extinguishing magnetic field generation unit 85 composed of a hairpin type or ring type conductor pattern is provided. S = 0 and S = -1 Magnetic bubbles with unknown domain wall state
It is generated by the VBL counting unit and is sequentially guided to the transfer path and transferred. In the annihilation magnetic field generating section 85 on the way, as shown in FIG. 12, a bias magnetic field of H _o <H <▲ H ^′ ₀ ▼ is applied. Then, the magnetic bubble in the state of S = 0 disappears, and the magnetic bubble in the state of S = -1 does not disappear. Only the magnetic bubbles that did not disappear are detected by the detector attached to the end of the transfer path 31.
Detected as V _s . As shown in FIG. 15 (b), by detecting V _s of J in N clock timings of the rotating magnetic field H _r for which this magnetic bubble is to be detected,
It turns out that the VBL pair existed in the first information magnetic bubble.

Even if this magnetic bubble transfer path is a two-layer conductor current-across magnetic bubble transfer path as shown in FIG. 16, it is clear that the effect of this means does not change at all.

(Effects of the Invention) The following effects can be obtained by carrying out the present invention. First, since a single magnetic bubble has a plurality of information, it is possible to easily increase the storage density even with the same exposure / etching technology level as the conventional magnetic bubble memory technology. About 32 VBL pairs can be easily held on the domain wall around one magnetic bubble. This corresponds to the fact that a maximum of 5 bits of information is stored in one magnetic bubble. A magnetic bubble memory device using the ion implantation method can easily achieve a storage density of 16 Mb / cm ² . Applying the invention to this, 80
A memory density of Mb / cm ² is possible.

The VBL pair writing and number counting unit of the present invention need only be provided for one stripe magnetic domain. Therefore,
VBL vs. write and VBL for conventional Bloch line memory devices
The pair read function can be used in a simpler form, and the pattern processing technique is not limited by providing a large number of these portions. That is, it can be said that the conventional Bloch line memory device can be easily put into practical use.

Further, according to the manufacturing method of the present invention, stable existence of the VBL pair in the domain wall of the magnetic bubble, which has been impossible with the ion-implanted magnetic bubble memory device having the high-density magnetic bubble transfer method, is enabled. . For this reason, the technology of the high-density magnetic bubble memory device immediately improved the storage density by about 5 times.

[Brief description of drawings]

1 and 2 are views showing an information storage method of the present invention,
FIG. 3 is a diagram showing a driving method of the information storage element of the present invention,
4 to 9 are views for explaining the operation of the vertical block line pair (VBL pair) counting section in the information storage element of the present invention, and FIG. 10 is the domain wall of the magnetic bubble corresponding to the presence or absence of the VBL pair. FIG. 11 is a state diagram, FIG. 11 and FIG. 12 are principle diagrams for discriminating magnetic bubbles having different domain wall states, and FIGS. 13 to 14 show a first domain wall state discriminating means in the information storage element of the present invention. Figure, first
15 to 16 are views for explaining the second domain wall state discriminating means. In the figure, 1 is a magnetic bubble, 2 is a domain wall, and 3 and 3a are VBL.
On the other hand, 3b is a position without VBL, 3c is VBL, 4 is a magnetization direction, and 5 is a minor loop magnetic bubble transfer path. 10 is a magnetic bubble holding material, 11 is a memory chip, 15 is a striped magnetic domain, 20 is a magnetic bubble generator, 21 and 31 are magnetic bubble transfer paths, 22 is a VBL pair write section, 23 and 33 are major line transfer paths, Reference numerals 24 and 34 are transfer gates, 30 and 30 'are magnetic bubble detectors, 32 is a VBL pair counter, 35 is a VBL pair fixed pattern, 36 and 36' are bias magnetic field modulation conductors, 37 is a stripe magnetic domain tip extension pattern, 38 , 38 'is a stripe domain chop pattern, 40 is an in-plane magnetic field, 41 is a bias magnetic field pulse,
42 is an in-plane magnetic field for fixing VBL, 43 is a rotating magnetic field, 60 is a data input unit, 61 is a modulator, 62 is a counter, 70 is a data output unit, 71 is a demodulator, 72 is a counter, 81, 82, 83 Is a magnetic bubble transfer pattern, 83a and 83b are magnetic bubble stable positions,
Reference numeral 84 is a conductor pattern, and 85 is an S = 0 bubble extinction magnetic field pattern.

Claims (3)

[Claims] 1. A thin piece of magnetic material capable of holding and transferring magnetic bubbles, a plurality of loop-shaped magnetic bubble transfer paths provided on the thin pieces, and a magnetic bubble transfer path for inputting information adjacent to the loop-shaped transfer path. And an information output bubble transfer path, a magnetic bubble transfer gate connecting the two types of transfer paths, a magnetic bubble and a stripe shape provided on the information input magnetic bubble transfer path and the information output bubble transfer path. In a magnetic storage element having a magnetic domain mutual conversion means, a means for writing a pair of vertical Bloch lines on a domain wall of the striped magnetic domain, and a means for detecting the number of vertical Bloch line pairs in the striped magnetic domain, l ₁ , l ₂ , ..., L _n ) (where l _i = 1 or 0) Injecting the vertical Bloch line pair of the above into the boundary domain wall of the magnetic bubble, thereby storing n-fold information for each one magnetic bubble. 2. A thin piece of magnetic material capable of holding and transferring magnetic bubbles, a plurality of on-loop magnetic bubble transfer paths provided on the thin pieces, and a magnetic bubble transfer path for inputting information adjacent to the loop-shaped transfer path. And an information output bubble transfer path, a magnetic bubble transfer gate connecting the two types of transfer paths, a magnetic bubble and a stripe shape provided on the information input magnetic bubble transfer path and the information output bubble transfer path. In the information storage element, there is provided a magnetic domain mutual conversion means, a means for writing a pair of vertical Bloch lines on a domain wall of the striped magnetic domain, and a means for detecting the number of vertical Bloch line pairs in the striped magnetic domain. The line logarithm detection means includes a comb-shaped conductor pattern forming a Bloch line stable position having a maximum Bloch line logarithm of -1, and a local bias magnetic field modulation conductor pattern. A Bloch line-to-magnetic bubble conversion unit consisting of a striped magnetic domain tip stretched conductor pattern and a striped magnetic domain chopping conductor pattern, and magnetic bubbles having different domain wall states generated thereby are moved in a gradient bias magnetic field. An information storage element comprising a vertical Bloch line pair number detecting means for discriminating magnetic bubbles in a domain wall state and counting the number of magnetic bubbles in a specific domain wall state. 3. A thin piece of magnetic material capable of holding and transferring magnetic bubbles, a plurality of loop-shaped magnetic bubble transfer paths provided on the thin pieces, and a magnetic bubble transfer path for inputting information in proximity to the loop-shaped transfer path. And an information output bubble transfer path, a magnetic bubble transfer gate connecting the two types of transfer paths, a magnetic bubble and a stripe shape provided on the information input magnetic bubble transfer path and the information output bubble transfer path. In the information storage element having mutual conversion means for magnetic domains, means for writing a pair of vertical Bloch lines in the domain wall of the striped magnetic domain, and means for detecting the number of vertical Bloch line pairs in the striped magnetic domain, The Bloch line logarithmic detection means includes a comb-shaped conductor pattern forming a Bloch line stable position with a maximum Bloch line logarithm of -1, and a local bias magnetic field modulation conductor pattern. A magnetic bubble transfer path in which a Bloch line-to-magnetic bubble conversion unit consisting of a striped magnetic domain tip stretched conductor pattern and a striped magnetic domain chopping conductor pattern, and magnetic bubbles having different domain wall states generated by the Bloch line Then, the number of magnetic bubbles having different domain wall states is counted by extinguishing the magnetic bubbles in a specific domain wall state by applying a local bias magnetic field when applying the local magnetic field application section provided in this transfer path. An information storage element having a means for detecting the number of vertical Bloch line pairs.